docs: update features.md note about ESM imports in web workers (#13223)

docs/guide/features.md

@@ -541,7 +541,7 @@ import MyWorker from './worker?worker'
 const worker = new MyWorker()
 ```
 
-The worker script can also use `import` statements instead of `importScripts()` - note during dev this relies on browser native support and currently only works in Chrome, but for the production build it is compiled away.
+The worker script can also use ESM `import` statements instead of `importScripts()`. **Note**: During dev this relies on [browser native support](https://caniuse.com/?search=module%20worker) (currently not supported in Firefox), but for the production build it is compiled away.
 
 By default, the worker script will be emitted as a separate chunk in the production build. If you wish to inline the worker as base64 strings, add the `inline` query: